The use of freezing point depressants to remove hard-packed snow and ice from pavements has been a common practice by highway maintenance crews for decades. Each new freezing point depressant or chemical that is brought into the market has its own unique set of properties. Some of the depressants are thicker than others, while others are more concentrated. Others may have unpleasant odors, while others may work only at warm temperatures.
One of the first chemicals to be used by road maintenance crews was sodium chloride (NaCl), more commonly known as road salt. Initially, this chemical was applied as a solid, which rapidly went into solution in the presence of snow, ice or water. Typically, chemicals such as road salt have been applied during storms when temperatures were 20° F. or warmer in an attempt to melt snow as it fell and limit bonding to the pavement. Chemicals have also been applied after a storm to remove snow and ice that has bonded to the surface.
New methods of snow and ice removal are constantly being sought. More particularly, methods of snow and ice removal that do not adversely affect the environment and methods that decrease the volume of chemicals required are most sought.